Rotating surface of revolution reactor with feed and collection mechanisms

ABSTRACT

A reactor including a rotatable disc ( 3 ) having a trough ( 13 ) in an upper surface ( 5 ) thereof. Reactant ( 15 ) is supplied to the trough ( 13 ) by way or a feed ( 4 ), the disc ( 3 ) is rotated at high speed, and the reactant ( 15 ) spills out of the trough ( 13 ) so as to form a film ( 17 ) on the surface ( 5 ). As the reactant ( 15 ) traverses the surface ( 5 ) of the disc ( 3 ), it undergoes chemical or physical process before being thrown from the periphery of the disc ( 3 ) into collector means ( 7 ).

This application is a 35 USC 371 National Stage of PCT/GB/00/00521 filedFeb. 17, 2000.

The present invention relates to a rotating surface of revolutionreactor provided with various feed and collection mechanisms for inputand output products.

The invention makes use of rotating surfaces of revolution technology(hereinafter RSORT) (commonly known as spinning disc technology).

BACKGROUND

The spinning disc concept is an attempt to apply process intensificationmethods within the fields of heat and mass transfer. The technologyoperates by the use of high gravity fields created by rotation of a discsurface causing fluid introduced to the dire surface at its axis to flowradially outward under the influence of centrifugal acceleration in theform of thin often wavy films. Such thin films have been shown tosignificantly improve the heat and mass transfer rates and mixing. Thetechnology was developed for typical heat and mass transfer operationssuch as heat exchanging, heating, cooling and mixing, blending and thelike, for example as disclosed in R J J Jachuck and C Ramshaw, “ProcessIntensification: Heat transfer characteristics of tailored rotatingsurfaces”, Heat Recovery Systems & CHP, Vol. 14, No 5, p475-491, 1994.

More recently the technology has been adapted for use as a reactingsurface for systems which are heat and mass transfer limited, forexample for the reaction of substrates which are highly viscous duringat least a stage of the reaction and cause problems in achieving goodmixing and product yields.

Boodhoo, Jachuck & Ramshaw disclose in “Process Intensification:Spinning Disc Polymeriser for the Manufacture of Polystyrene” the use ofa spinning disc apparatus in which monomer and initiator is reacted byconventional means to provide a pre-polymer which is then passed acrossthe surface of a spinning disc at elevated temperature providing aconversion product in the form of polymerised styrene.

EP 0 499 363 (Tioxide Group Services Limited) discloses another use forspinning disc technology in photo catalytic degradation of organicmaterials such a hydrocarbons. A solution of salicylic acid and titaniumdioxide catalyst was passed across the surface of a rotating disc andirradiated with ultra violet light.

These publications therefore disclose the use of spinning disctechnology for heating and mass transfer in inert and reactive systems.

GB 9903474.6 (University of Newcastle), firm which the presentapplication claims priority and the disclosure of which is herebyincorporated into the present application by reference, describes theuse of RSORT in the conversion of a fluid phase substrate by dynamicheterogeneous contact with an agent. In this application, it isdescribed how it has surprisingly been found that spinning disctechnology may be further adapted to apply process intensificationmethods not only within the fields of heat and mass tar but also withinthe field of heterogeneous contacting. Furthermore, it is described howit has surprisingly been found that the quality of the product obtainedis of higher quality than that obtained by conventional processinghaving, for example, a higher purity or, in polymers, a narrowermolecular distribution.

In addition to this, spinning disc technology can be used to obtainproducts not readily obtainable by other technology.

According to the present invention, there is provided a reactorapparatus including a support element adapted to be rotatable about anaxis, the support element having a surface, feed means for supplying atleast one reactant to the surface of the support element and collectormeans for collecting product from the surface of the support element,characterised in that the surface includes an undercut trough into whichthe at least one reactant is directly supplied by the feed means whenthe reactor apparatus is in use, and in that, upon rotation of thesupport element, the at least one reactant forms a generally annularfilm within the at least one undercut trough and passes therefrom acrossthe surface of the support element.

SUMMARY

It is to be understood that the term “reactant” is not limited tosubstances which are intended to undergo chemical reaction on thesurface of the support element, but also includes substances which areintended to undergo physical or other processes such as mixing orheating. Similarly, the term “product” is intended to denote thesubstance or substances which are collected from the surface of thesupport element, whether these have undergone chemical or physicalprocessing or both. In addition, although it is envisaged that mostreactants and products will be in the liquid phase, the apparatus can beused with any suitable fluid phase reactants and products, includingcombinations of liquid, solid and gaseous reactants and product. Forexample, solid phase substances in substantially free-flowingparticulate form can have macroscopic fluid flow properties.

The depth of the trough may be selected in accordance with reactionrequirements. For example, for photochemical reactions in which UV lightis shone onto the reactant, it is preferred for the trough to berelatively shallow, for example having a depth of the same order ofmagnitude or within one order of magnitude as the expected thickness ofa film of reactant formed across the surface of the support element whenrotating at an appropriate speed.

An RSORT apparatus (commonly known as a spinning disc reactor) generallyincludes within a conversion chamber a rotating surface or an assemblyof a plurality of these which is rid about an axis to effect transfer ofone or more reactants from the axis preferably radially across therotating surface.

An RSORT apparatus as hereinbefore defined comprising a rotating surfaceas hereinbefore defined has a number of advantageous constructionalfeatures according to the present invention.

The axis of rotation of the rotating surface or support member may besubstantially vertical, in which cals gravity tends to pull reactantsdownwardly with respect to the surface or support member. This may beadvantageous with less viscous reactants. Alternatively, the axis ofrotation may be generally horizontal, which can achieve improved mixingof reactants provided that these are appropriately retained on thesurface of the support member.

Any suitable feed means may be provided to feed the at least onereactant onto the rotating surface. For example, the feed means maycomprise a feed distributor in the form of a “shower head”, a “necklace”of outlets or a simple, preferably adjustable, single point introductionsuch as a “hose-pipe type” feet means. Preferably, the feed meanscomprises a feed distributor having a plurality of uniformly spacedoutlets for the at least one reactant on to the rotating surface ashereinbefore define. The feed means may also include means for applyingUV, IR, X-ray. RF, microwave or other types of electromagnetic radiationor energy, including mimetic and electric fields, to the reactants asthey are fed to the trough, or may include means for applying vibration,such as ultrasonic vibration, or heat.

The feed means may be provided at any suitable position with respect tothe rotating surface which allows feed of the reactant. For example, thefeed means may be axially aligned with the rotating surface for axialfeed. Alternatively, the feed means may be positioned such that the feedis spaced from the axis of the rotating surface. Such a position maylead to more turbulence and an enhanced mixing effect.

In one embodiment, feed mean may comprise a single feed to the troughwhich is preferably situated on or coaxial with the axis of rotation ofthe rotating surface. In this embodiment, reactant flows form the feedoutlet into the tough and is subsequently spread out of the tough on tothe rotating surface by centrifugal force. In a preferred embodiment,the rotating element as hereinbefore defined comprises a trough situatedon the axis of rotation.

The trough as hereinbefore defined may be of any suitable shape such ascontinuous or annular. For example it may have a continuous concavesurface comprising part of a sphere, such as a hemispherical surface, orit may have an inner surface joined to the rotating by at least oneconnection wall or at least two, in the case where the trough isannular. The inner surface and connection wall may be of any form whichallows the function of a trough to be fulfilled. For example the innersurface may be parallel to the rotating surface or concave or convex.The connection wall may comprise a single circular or avoid wall or aplurality of straight walls. The walls may diverge or converge towardsthe rotating surface.

Preferably, a single circular wall is provided which converges towardsthe rotating surface to form an undercut tough. This shape generates areservoir which enhances a circumferential distribution of the reactantflow. Alternative means for forming an undercut trough are alsoenvisaged. For example, where the trough is generally annular in shape,an outer wall may be provided as above, and an inner wall having anysuitable shape may serve to define an inner edge to the trough. Theundercut portion of the trough should generally be provided as an outerwall so as to help prevent uncontrolled egress of reactant from thetrough to the surface under the influence of cents force as the supportelement is rotated.

Advantageously, a matrix may be provided in the trough so as to helpreactant present in the trough to rotate with the support element,hereby helping to achieve substantially uniform flow from the troughacross the surface. The matrix may be in the form of a plug of fibrousmesh, such as metal or plastics wool, or may take the form of aplurality of projections which are secured to an inner surface of thetrough. Other matrix means will be apparent to the skilled reader. Insome embodiments, the matrix is manufactured of a material which isinert with respect to the at least one reactant or the product and whichis not significantly affected by temperature and other variable processconditions. Alternatively, the matrix may be made of a material whichdoes interact with the at least one reactant or the product, such as aheterogeneous catalyst (e.g. nickel, palladium or platinum or anysuitable metal or alloy or compound therof). Where the matrix is madeout of an electrically conductive material, it may be possible to supplyan electric current therethrough and thus to provide heating means forheating the at least one reactant within the trough.

In a further embodiment, there may be provided a plurality of feedsadapted selectively to supply one or more to a plurality of troughsformed in the surface. For example, where the support element isgenerally disc-like and has a substantially central axis of rotation,there may be provided a first central trough centered on the axisorientation and feed means for supplying at least one reactant to thefirst trough, and at least one further trough, preferably also centeredon the axis of rotation and having an annular configuration, the atleast one further trough being provided with feed means for supplying asecond reactant, which may be the same as or different from the firstreactant, to the at least one further trough. It will be apparent to theskilled reader that a plurality of troughs may be provided in a similarmanner on support elements with shapes other than generally disc-like.

By providing a plurality of troughs and feeds, a sequence of reactionscan be performed across the surface of the support element. For example,two reactants may be supplied to the first trough in which some mixingand will take place. As the support element rotates, the reactants willspread from the first trough to the surface of the support element,where further reaction and mixing takes place, and thence into a secondannular trough concentric with the first trough. A third reactant maythen be supplied to the second trough, and further mixing and reactionwill take place as the third reactant and the two initial reactants andany associated product are spread from the second trough onto thesurface of the support element for further mixing and reaction. Becausethe direction of travel of the reacts and products is outwards from theaxis of rotation, a controlled series of reactions can be carried outacross the surface of the support member.

In some embodiments, one of the reactants may be a liquid phasecomponent and another may be a gaseous phase component. In theseembodiment, the rowing support member is advantageously contained withina vessel so as to allow the concentration of the gaseous phase componentin the vicinity of the surface to be controlled. The liquid componentmay be fed to the surface of the disc as described above, and thegaseous component supplied to the vessel. A rotary impeller or fan orsimilar device may be mounted close to the rotating surface and drivenso as to suck the gaseous phase component from a region surrounding theperiphery of the rotating surface towards the centre of the rotatingsurface while the liquid phase component travels from the centre of thesurface towards its periphery due to the rotation of the rotatingsurface. Where, for example, the support element is a disc, the impelleror fan may take the form of a generally disc shaped structure mountedcoaxially with the support element and close thereto. A surface of theimpeller or fan facing the rotating surface of the support element maybe provided with blades or vanes such that rotation of the impeller orfan serves to suck the gaseous phase component from a periphery of thesac and the impeller or fan towards the centre of the surface. Byproviding a counter-current flow of the gaseous and liquid phasecomponents, heat or mass transfer between the components is muchimproved, since the concentration of unreacted liquid phase reactant islowest at the periphery of the disc, and therefore benefits from a highconcentration of the gaseous phase component so as to ensure fullreaction.

Any suitable collection means may be provided for collection of theproduct as it leaves the rotating surface at its periphery. For example,there may be provide a receptacle in the form of a bowl or trough atleast partially surrounding the rotating element or other fixed part ofthe apparatus. The collection means may additionally comprise adeflector positioned around the periphery of the rotating surface todeflect product into the collection means the deflector is preferablypositioned at an acute angle to the rotating surface.

The components of the collection means, such as the bowl or trough ordeflector, may be coated or otherwise provided with a heterogeneouscatalyst appropriate to the reactants being reacted on the supportelement or may even consist entirely of a material which acts as aheterogeneous catalyst. Furthermore, the components of the collectionmeans may be heated or cooled to a predetermined temperature so as toenable control over reaction parameters for example by serving to haltthe reaction between reactants as these leave the surface in the form ofproduct. Feed means for supplying a reactant to the product leaving thesurface may also be provided. For example, there may be provided feedmeans for feeding a quenching medium to product in the collection meansso as to halt chemical or other reactions between reactants when thesehave left the surface.

The collection mea may further comprise outlet means of any suitableform. For example, there may be a single collection trough runningaround the periphery of the disc or a collection bowl partiallysurrounding the rotating element.

Outlet means may also be provided in the collection means and these maytake the form of apertures of any size and form situated at any suitableposition of the collection means to allow egress of the product. In onepreferred embodiment, the outlet means are situated to allow verticalegress of the substrate in use.

Alternatively, the collection means may comprise an outer wall providedat the periphery of the support element so as to prevent product frombeing thrown from the surface, and at least one pilot tube which extendsinto the product which is restrained at the periphery of the supportelement by the outer wall. The outer wall may converge generally towardsthe axis of rotation of the support member so as better to retainproduct while the support element is undergoing rotation, although otherwall configurations, such as generally parallel to or divergent from theaxis of rotation may also be useful.

Embodiments of the present invention include multiple sup elements,which may share a common axis of rotation and which may be mounted on asingle rotatable shaft, or which may be provided with individualrotatable shafts. The collection means associated with any given supportelement may be connected to the feed means associated with any othergiven support element so as to link a number of support elements inseries or parallel. In this way, a reaction may be conducted across anumber of support elements in series or parallel. The collection meansof a first support member may be directly connected to the feed means ofa second support member, or may be connected by way of a processing unitsuch as a pump, extruder, heater or hem exchanger or any otherappropriate device. This is especially useful when dealing with viscousproducts, such as those which are obtained in polymerisation reactions,since the viscous product of a first support element may be processed soas to acquire more favourable physical characteristics before being usedas the reactant feed for a second support element.

For example, where the collection means comprises an outer wall on thesurface of the support element as described above, a number of supportelements may be coaxially mounted on a single rotatable shaft so as toform a stack of support elements. A reactant fed is led to the trough ofa first support element, and a collector in the form of a pilot tube hasits tip located near the surface of the fist support element in thevicinity of the wall so as to take up product from this region. An endof the pilot tube remote fin the tip is led to the trough of a secondsupport element so as to allow the product of the first support elementto serve as the reactant for the second support element thereby allowinga number of reactions to take place in series. Alternatively, a numberof parallel fees may supply the same at least one reactantsimultaneously to the troughs of a number of support elements and anumber of parallel pilot tube collectors may gather product from aperipheral region of each support element, thereby allowing a reactionto take place across a number of sort elements in parallel.

It is also envisaged that product collected from the periphery of asupport element may be recycled as feed for that support element. Thisis useful for processes requiring an extended contact time for thereacts. The product may be fully or only partially recycled, dependingon requirements.

Reference herein to a rotating surface is to any continuous or discreteplanar or three dimensional surface or assembly which rotatesapproximately or truly about an axis, and preferably is reference to anapproximate or true rotating surface of revolution. An approximaterotating surface of revolution may comprise an asymmetric axis and/ordeviation in the surface body and/or circumference creating an axiallyor radially undulating surface of revolution. A discrete surface may bein the form of a mesh, grid, corrugated surface and the like.

Reference herein to a substantially radially outward flowing film ashereinbefore defined is to any fluid film which may be created bydynamic contact of the fluid phase reactant and the rotating surface ashereinbefore defined, suitably the fluid phase reactant is contactedwith the rotating sure at any one or more surface locations and causedto flow outwardly by the action of central force. A film may be acontinuous annulus or may be a non-continuous arc at any radiallocation. The substrate may provide a plurality of films in dynamiccontact with a rotating surface as hereinbefore defined.

For example processes requiring extended contact time may be carried outin continuous manner with use of a recycle of fluid exiting at theperiphery of the rotating surface towards the axis of the rotatingsurface enabling sequential passes of fluid across the surface. Incontinuous steady state operation an amount of fluid exiting the surfacemay be drawn off as product and an amount may be returned by recycle forfurther conversion with an amount of fresh reactant feed.

The process of the invention as hereinbefore defined may operated in asingle or plural stages. A plural stage process may comprise a firstpre-process stage with further post-process or upgrading stages, and maybe carried out batchwise with use of a single rotating surface ashereinbefore defined or may be carried out in continuous manner withmultiple rotating surfaces in series.

Second or more reactants may be added to the feed reactant as it passesfrom one rotating assembly to the next or be added directly to therotating assembly anywhere between the axis of rotation or the exit fromthe assembly. In certain cases a multi-step process may be achieved byreactant addition or additions between the axis of rotation and the exitof a single rotating assembly to achieve more than one process step in asingle pass. It is also possible to have different regions of therotating surface at different temperatures and conditions and havedifferent surface geometries as appropriate to the process needs.

It will be apparent that the process of the invention may be controlledboth by selection of a specific rotating surface for the support elementand by selecting process variables such as temperature, speed ofrotation, rate of reactant feed, conversion time and the like.Accordingly the process of the invention provides enhanced flexibilityin process control including both conventional control by means ofoperating conditions, and additionally control by means of rotatingsurface type.

The apparatus may further comprise any suitable control system. Such acontrol system may regulate the temperature or contact time of reactantsby means of speed of rotation, rate of substrate feed and other processparameters to obtain an optimum result.

The apparatus as hereinbefore defined may comprise means for optimisingprocess conditions. For example, means for imparting an additionalmovement to the rotating surface, and thus to the reactant, may beprovided. Such movement could be in any desired plane or plurality ofplanes and preferably comprises vibration. Any suitable vibration meansmay be provided, such as flexible mounting of the surface or off centremounting, both inducing passive vibration or active vibration means,such as a mechanical element in contact with the rotating element andvibrating in a direction parallel to the rotating element axis.Preferably a passive vibration means is provided in the form of offcentre mounting of the rotating element on its axis of rotation.Vibration may alternatively be provided by an ultrasonic emitter incontact with the rotating element for vibration in any desired plane orplurality of planes.

The rotating surface may have any shape and surface formation tooptimise process conditions. For example the rotating surface may begenerally planar or curved, frilled, corrugated or bent. The rotatingsurface may form a cone or be of generally frustoconical shape.

In one preferred embodiment the rotating surface is generally planar andpreferably generally circular. The periphery of the rotating surface mayform an oval, rectangle or other shape.

In another preferred embodiment the rotating surface is provided as theinner surface of a cone. The apparatus may comprise at least one coneand at least one other rotating surface or at least one pair of facingcones positioned so as to allow a two stage process with one or morereactants fed to each cone. Preferably product exits a smaller cone (orother surface of rotation) in a spray on to the surface of a larger cone(or other surface of rotation) by which it is at least partiallysurrounded and for the surface of which a further reactant is fed byfeed means as hereinbefore defined, to allow mix of the product andreactant on the larger rotating surface. Preferably, means are providedsuch that the two cones counter rotate. Such an arrangement enhancesmixing and intimate contact of the reactants and reduces the requiredphysical contact time. Alternatively, means are provided such that thecones co-rotate or one is stationary.

In another embodiment, there may be provided two generally planarsupport elements mounted coaxially and generally parallel to each otheron an axis of rotation. The facing surfaces of the support elements maybe provided with at least one generally circular wall defined about theaxis of rotation, and preferably a plurality of concentric walls, thewalls being divergent with respect to the axis of rotation of theirrespective support element. The walls on one support element arepositioned out of phase with the walls on the other support element sothat the walls fit between each other when the support elements arebrought close together. Reactant may be supplied to a region within theinnermost wall on one of the support elements. Upon rotation of thesupport elements, the reactant will tend to move along an interiorsurface of the divergent wall towards a region within the next wall onthe opposed support element, and thence onto an interior surface of thesaid next wall back towards the first support element. The reactant maycontinue to move back and forth between the support members so as toprogress in a zig-zag manner in a generally radial direction away fromthe axis of rotation along the interior surfaces of the intermeshedwalls towards an outer collection point as described above. In this way,a compact reactor with a high surface area is achieved, the surfaceconsisting of the interior surfaces of all the concentric walls. Thesupport elements may rotate together in a given direction, or may roteat different speeds in the same direction, or may rotate at the samespeed or at different speeds in opposed direction.

A rotating surface of any shape and surface formation as hereinbeforedefined may be provided with surface features which serve to promote thedesired process. For example, the surface may be micro or macroprofiled, micro or macro porous, non stick, for example may have arelease coating, may be continuos or discontinuous and may compriseelements such as mesh, for example woven mesh, reticulate foam, pelletscloth, pins or wires, for enhanced surface area, enhanced or reducedfriction effect, enhanced or reduced laminar flow, shear mixing ofrecirculation flow in axial direction and the like.

In one preferred embodiment, mixing characteristics of the rotatingsurface are enhanced by the above features or the like provided on or inthe rotating surface. These may be provided in any suitable regular orrandom arrangement of grids, concentric rings, spider web or likepatterns which may be suitable for a given application.

Alternatively or additionally to any other surface feature, radiallyspaced pins in the form of circles or segments of circles may beprovided.

In another preferred embodiment, a porous surface coating is provided,which aids processing of certain reacts. Such a coating may be providedin combination with any other of the aforementioned surface features.

Surface features in the form of grooves may be concentric or may be ofany desired radially spaced form. For example, the grooves may form“wavy” or distorted circles for maximised mixing.

Grooves may be parallel sided, or may have one or both sides whichdiverge to form undercut grooves or which converge to form taperedgrooves. Preferably, the grooves are undercut to promote mixing.

Grooves may be angled to project towards or away from the axis of therotating surface to enhance or reduce undercut or taper.

Energy transfer means may be provided for the rotating surface orreactant or product as hereinbefore described. For example heating meansmay be provided to heat the reactant, for example, as part of the feedmeans. Additionally, or alternatively heating means may be provided toheat the rotating element in the form of radiant or other heaterspositioned on the face of the rotating element which does not comprisethe rotating surface for conversion. Preferably, radially spaced,generally circular radiant heaters are provided.

Any preferred cooling or quenching means may be provided in a suitableposition to cool the reacted substrate. For example cooling coils or aheat sink may provide cooling by heat exchange, or a reservoir of quenchmay provide cooling or reaction termination by intimate mixing in thecollection means.

For a better understanding of the present invention and to show how itmay be carried into effect, reference shall now be made by way ofexample to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows a spinning disc apparatus in schematic form;

FIG. 2 shows a detail of a spinning disc having a central trough;

FIG. 3 shows a detail of a spinning disc having an annular trough;

FIG. 4 shows a number of spinning discs in schematic form andoperatively arranged in series;

FIG. 5 shows a number of spinning discs in schematic form andoperatively arranged in parallel;

FIG. 6 shows two coaxial spinning discs in schematic form and providedwith a pump unit for transferring product from one disc as feed to thesecond disc;

FIG. 7 shows two rotating support elements with intermeshing concentriccircular walls; and

FIG. 8 shows a spinning disc provided with a rotary impeller;

FIG. 9 shows the spinning disc of FIG. 3 rotated at an angle;

FIG. 10 shows the spinning disc of FIG. 3 rotated at a perpendicularangle;

FIG. 11 shows a plurality of troughs provided on the surface and eachtrough has associated with it a feed means; and

FIG. 12 shows a plurality of support elements mounted on a plurality ofaxes of rotation.

DETAILED DESCRIPTION

FIG. 1 illustrates a spinning disc apparatus of the present invention.The apparatus is enclosed in vessel (1) having at its axis a drive shaft(2) supporting a spinning disc (3). Feed means (4) provides reactant toan undercut annular trough (13) provided in the surface (5) of the disc(3) about its axis (6). Rotation of the disc (3) causes reactant to flowradially outwards, whereby it contacts the surface (5) of the spinningdisc (3). Fluid is collected at the peripheral edges of the disc (3) bymeans of collection trough (7) and may be rapidly quenched by means ofcooling coils (8). A skirt (9) prevents meniscal draw back of fluidcontaminating the drive shaft mechanism. Inlet means (10) enablecontrolled environment conditions to the provided, for example anitrogen atmosphere. Outlet vent means (11) enable the venting ofatmospheric gases or gases evolved during operation. Observation meansare provided by means of windows (12) to observe the progress of theconversion.

The apparatus of FIG. 1 may be started up and operated as described inExample 1 below. In the case that the process is an exothermicconversion, cooling coils (8) may be used to quench the collectedproduct in the trough (7). The spinning disc (3) is provided withheating coils (not shown) which may be used to initiate or maintainconversion. The disc (3) or the reactor vessel (1) may be provided witha source of radiation (100), means for applying an electric or magneticfield and the like as described, at or above the disc surface (5) or atthe wall of the reactor vessel (1).

In FIG. 2 there is shown an axially located central trough (14) which iscontinuous and forms a well situated on the axis of rotation (6) of therotating surface (5) of a disc (3). Rotation causes reactant (15)supplied by the feed means (4) to flow to the wall and form an annularfilm (16) within the trough (14). The annular film (16) then spills overonto the surface (5) of the disc (3) to form a film (17) on the surface(5). Eccentric axis of rotation (6′) is also shown.

In FIG. 3 the trough (13) is annular and forms a channel co-axial aboutthe axis of rotation (6) of the disc (3). Rotation assisted by thetrough profile causes reactant (15) to flow into the trough (13) and tothe wall thereof and form an annular film (16) within the trough (13)before spilling over onto the surface (S) of the disc (3) in the form ofa film (17).

FIG. 4 shows three discs (3) coaxially mounted on a drive shaft (2)which defines an axis of rotation (6). Each disc (3) has a centraltrough (13) into which reactant (15) may be fed, and a peripheral wall(18). Reactant (15) is supplied to the trough (13) of the topmost disc(3) by way of feed means (4), and then spreads out over the surface (5)of the disc (3). Product (19) is collected from the vicinity of theperipheral wall (18) by way of a pilot tube collector (20), which thenfeeds product (19) to the trough (13) of the next disc (3) down on thedrive shaft (2). In this way, a process can be performed across a numberof discs (3) in series. Means for applying vibration (200) is alsoshown.

FIG. 5 shows three discs (3) coaxially mounted on a drive shaft (2)which defines an axis of rotation (6). Each disc (3) has a centraltrough (13) into which reactant (15) may be fed, and a peripheral wall(18). Reactant (15) is supplied in parallel to the trough (13) of eachdisc (3) by way of feed means (4), and then spreads out over thesurfaces (5) of the discs (3). Product (19) is collected from thevicinity of the peripheral walls (18) by way of pilot tube collectors(20), which are also connected in parallel. In this way, a process canbe performed across a number of discs (3) in parallel. Means forapplying vibration (200) is also shown.

FIG. 6 shows two discs (3) coaxially mounted on a drive shaft (2) whichdefines an axis of rotation (6). Each disc (3) has a central trough (13)into which reactant (15) may be fed by feed means (4) before spillingonto the surface (5) of each disc (3). A collector trough (21) isprovided about the periphery of each disc (3) so as to collect product(19) thrown from the discs (3). An outlet from the upper collectortrough (21) passes through a pump or extruder (22) before leading to thetrough (13) of the lower disc (3) as feed means (4). This arrangement issuitable for use with viscous reactants and products. Collector means 90are also shown.

FIG. 7 shows a pair of planar rotating support elements (80, 81)coaxially mounted on an axis of rotation (6). The facing surfaces (82,83) of the support elements (80, 81) are each provided with a pluralityof concentric circular walls (84, 85, 86, 87), with walls (84, 86)mounted on surface (82) and walls (85, 87) mounted on surface (83). Thewalls (84, 85, 86, 87) are divergent with respect to the axis ofrotation of their respective support element (80, 81) and are positionedso that they mesh with each other when the support elements (80, 81) arebrought together as shown. Reactant (15) is supplied to an interiorregion of wall (84) near surface (82) by a feed (4), and then proceedsto travel along an interior surface of wall (84) towards surface (83).When the reactant (15) reaches the top of wall (84), it spills over ontoan interior surface of wall (85) on support element (81) and travelsback towards support element (80) as shown. This process is repeateduntil the reactant (15) is thrown from the top of the outermost wall(87) into collecting means (not shown). By providing a convolutedsurface along which the reactant (15) may travel, a very compact reactormay be obtained. The support elements (80, 81) may co- orcounter-rotate, either at the same or at different rotational speeds.

FIG. 8 shows a spinning disc (3) with a surface (5) mounted on a driveshaft (2) inside a vessel (1) and provided with a feed (4) for a liquidphase reactant, such as an organic prepolymer. A rotary impeller (70) ismounted coaxially with the disc (3) and close to the surface (5), and asurface (71) of the impeller (70) facing the surface (5) is providedwith vanes (72). A gaseous phase reactant, such as nitrogen, is suppliedto the vessel (1) through an inlet (10). Upon rotation of the disc (3),the liquid phase reactant moves from the centre of the surface (5)towards the periphery thereof as described above. When the impeller (70)is appropriately rotated on a drive shaft (74), the gaseous phasereactant is sucked into the space (73) between the impeller (70) and thesurface (5) and moves towards the centre of the surface (5) against theflow of liquid phase reactant, thereby improving mass and/or heattransfer characteristics. Gaseous phase reactant and unwanted reactionby-products may be removed from the central region of the space (73) byway of a discharge pipe (75) to which at least a partial vacuum may beapplied. A partial seal (76) in the discharge pipe (75) may be providedso as to control the rate of gaseous phase reactant and by-productremoval.

EXAMPLE 1

Polymerisation of Ethylene Using a Catalyst Coated Disc

Phillips catalyst was coated onto the surface of a spinning discapparatus using methods as described hereinbefore. The coated disc wasmounted in a spinning disc apparatus.

The spinning disc apparatus used is shown in diagrammatic form in FIG.1. The main components of interest being:

-   -   i) Top Disc—A smooth brass disc of thickness 17 mm and diameter        500 mm capable of rotating around a vertical axis.    -   ii) Liquid Distributor—A circular copper pipe of diameter 100        mm, positioned concentrically over the disc, sprayed fluid        vertically onto the disc surface from 50 uniformly spaced holes        in the underside. Flowrate was controlled manually by a valve        and monitored using a metric 18 size, stainless steel float        rotameter. A typical fluid flow rate was 31.3 cc/s.    -   iii) Motor—A variable speed d.c. motor capable of rotating at        3000 rpm was used. The rotational speed was varied using a        digital controller calibrated for disc speeds between 0 and 1000        rpm. A typical rotational speed was 50 rpm.    -   iv) Radiant Heaters—3 radiant heaters (each consisting of two        elements) spaced equally below the disc provided heat to the        disc. The temperature was varied using a temperature controller        for each heater. Each heater temperature could be controlled up        to 400° C. Triac regulators were used to control the speed of        the controller response. (These remained on setting 10        throughout the tests).    -   v) Thermocouples and Datascanner—16 K-type thermocouples        embedded in the top disc gave an indication of the surface        temperature profile along the disc radius. Odd numbered        thermocouples 1 to 15 inclusive were embedded from underneath        the disc to a distance 3 mm from the upper disc surface. Even        numbered thermocouples, 2 to 16 inclusive were embedded from        underneath the disc to a distance 10 mm from the upper disc        surface. Each pair of thermocouple, i.e. 1 & 2 and 3 & 4 and 5 &        6 etc., were embedded adjacently at radial distances of 85 mm,        95 mm, 110 mm, 128 mm, 150 mm, 175 mm, 205 mm and 245 mm        respectively (see FIG. 3). The thermocouples were connected to        the datascanner which transmitted and logged the data to the PC        at set intervals using the DALITE Configuration and Monitoring        Software Package.    -   vi) Manual Thermocouple—A hand-held K-type thermocouple was used        to measure the bulk fluid temperature on top of the disc.

The rig was used in two arrangements. In one arrangement, feed wasconstantly added and the heated product was sent to the collectiontrough. In an alternative arrangement the rig was assembled with arecycle.

The spinning disc apparatus of FIG. 1 was started up and temperature androtational speed adjusted. When steady stage was achieved gaseousethylene was fed to the revolving catalyst coated disc surface at itaxis. Product was withdrawn in the collection trough at the periphery ofthe disc. Analysis revealed the product was high grade polyethylene.

Further advantages of the invention are apparent from the foregoing.

1. A reactor apparatus including a support element adapted to berotatable about an axis, the support element having a surface, feedmeans for supplying at least one reactant to the surface of the supportelement and collector means for collecting product from the surface ofthe support element, wherein the surface includes an undercut troughinto which the at least one reactant is directly supplied by the feedmeans, and in that, upon rotation of the support element, the at leastone reactant forms a generally annular film within the at least oneundercut trough and passes therefrom across the surface of the supportelement, further including a plurality of support elements wherein theplurality of support elements is mounted on a plurality of axes ofrotation and wherein a processing unit is provided between the collectormeans of the first support member and the feed means of the secondsupport member.
 2. A reactor as claimed in claim 1, wherein theprocessing unit is a pump, an extruder, a heater or a heat exchanger. 3.A reactor apparatus including a support element adapted to be rotatableabout an axis, the support element having a surface, feed means forsupplying at least one reactant to the surface of the support elementand collector means for collecting product from the surface of thesupport element, wherein the surface includes an undercut trough intowhich the at least one reactant is directly supplied by the feed means,and in that, upon rotation of the support element, the at least onereactant forms a generally annular film within the at least one undercuttrough and passes therefrom across the surface of the support element,wherein there is further provided a rotary impeller mounted close to thesurface and operable to generate a gaseous flow from a periphery of thesurface towards a central region thereof, this flow beingcounter-current to a flow of reactant on the surface.